Electropneumatic brake



AApril *12, 1938. i A. G. KERSHAW ET AL 2,113,621

` ELECTROPNEUMATIC BRAKE Filed DSO. l2, 1956 Z-SheetS-Sheet l lljlh 4'INVENTORS ARTHUR G. KERSHAW ARTHUR WSIMMONS `KENNETH H-LEEGH ATTORNEYApril l2, 19 A. G. KERsHAw ET AL zm ELECTROPNEUMATIC BRAKE 4 Filed Deo.l2, 1936 l 2 Sheets-Sheet 2 jlsllll alu R EL EASE APPLICATION INVENTORSARTHUR G- KERSHAW ARTHUR WSIMMONS KENNETH HALE ECH ATTORN EY Cil.

Patented Apr. 12, 1938 L.

UNITED STATES `Temelinv orFlcE ELECTROPNEUMATIC BRAKE PennsylvaniaApplication December 12, 1936, Serial No. 115,572 In Great BritainDecember 14, 1935 20 Claims.

v This invention relates to engineers brake control devices forelectropneumatically controlled fluid pressure braking apparatus andmore particularly to a brake control switch device of the self-lappingtype having electric contacts arranged to control the operation ofelectropneumatic valves in such a manner as to effect the automaticadjustment of the brake cylinder pressure in accordance with the settingof the control device.

One object of the invention is to provide an improved brake controlswitch of this character in which the operation of the contactscontrolling the electropneumatic valves is arranged to be directlyeffected bythe movement of the operating handle or lever of the switchdevice, the reverse or lapping operation of the contacts being effectedby an abutment subject to the fluid pressure obtaining in the brakecylinder or its equivalent without effecting any movement of the handleor lever from the position to which it was initially adjusted whichdetermines the `pressure acting upon the abutment necessary foreffecting its operation to cause the reverse operation of the contacts.

According to a further feature of the invention .the initial movement ofthe handle or lever from one position to another is arranged to effect arapid operation of the contacts, the continued movement of the handleeffecting the compression or extension of a suitable vspring Without.having any action .upon the contacts, the reverse operation of thesecontacts under the action of the brake cylinder pressure being similarlyrapidly effected only when the spring has been restored to its originalcondition.

In the accompanying drawings;

Fig. l is a View in front elevation of a previerred construction of anengineers control device embodying one form of the invention,

Fig. 2 is a view thereof rin sectional, rear elevation, and

Fig. 3 is a plan view of a portion of the control device shown inFg. l,associated with one form of brake equipment for illustrating anapplication thereof.

As shown in the drawings, the engineers control device comprises anoperating handle or lever I which is rigidly secured to a horizontalshaft 2 mounted in suitable bearings in a casing 4. The shaft 2 carriesan arm 5 rigidly secured at one end thereto while the outer end ispivotally connected at 6 to one end of a short link l the other `end ofwhich is pivotally connected at vI! to .the upper end of a substantiallyvertical floating lever 9. The opposite or lower end .of the lever 9 ispivotally connected at I0 tog-one end of a link II the `other end ofwhich is pivotally connected .at I2 to the yshorter yarm I3 of asubstantially vertical contact lever I4 having its fulcrum I5 at a xedpoint in the casing 4. 'Ihe longer Varm I6 of the contact lever carriesan insulated contact member or segment Il adapted to engage with xedflexible contacts I B, Isa. and ISU which are secured to and insulatedfrom the casing 4. The contact IB is in constant contact with segment I1for supplying thereto electric current from any suitable source such `asa battery 46. The contact IBa. is lconnected to an application .magnetvalve device 42 for controlling the operation thereof, and the contact.IIlb is connected to a release magnet valve device 43 for controllingits operation, as most clearly shown in Fig. 3. The segment I1 isstep-cut on either side to disengage the contact finger I8a at one timeand I8b at another time. 'I'he magnet valve devices 42 and 43 are ofusual construction adapted to control the supply and release .of uidunder pressure to and from a brake cylinder 44 for controlling theapplication and the release ofthe brakes; the magnet Valve device 42when energized being adapted to supply fluid under pressure from a mainreservoir 45 to said brake cylinder .and when deenergize-d to cut offsaid supply; the magnet valve device 43 being adapted when energized torelease fluid under pressure from said brake cylin- `der and whendeenergized to close the brake cylinder release communication. When bothmagnets l2 and 43 are deenergized the fluid under pressure is bottled inthe brake cylinder to effect holding of the brakes in `the usual manner.

An intermediate point I9 in the floating Alever 9 is pivotally connectedthrough an adjustable member 20 to a horizontal rod or stem 2| adaptedto .slide within the tubular piston rod .22 of an operating piston 23contained in .a cylinder 24 mounted in the casing 4. The louter end 25of the cylinder 24 beyond the piston 23 is in communication throughpassage 25 and pipe 21 with the brake cylinder. the pressure in W c`acts upon the piston 23 in opposition to the :.ction of a controlspring 28 interposed .between he opposite side of the piston 23 and thecorresrcsding end of the cylinder 24.

The tubular piston rod 22 is provided at each' collar 29 at the oppositeend abuts against a similar shoulder 32 formed on a cap 33 secure-d tothe end of the tubular piston rod 22. The rod 2| coupled to the floatinglever 9 passes loosely through the cap 33 and the sliding collars 29, 30and is provided with a shoulder 34 adapted to engage with the outer sideof the collar 29 and with a head 35 adapted to engage with the outerside of the other collar 30, a light compression spring 39 surroundingthe rod 2| being interposed between the two collars 29 and 3|).

The operation of the control device is as follows:-

Under release conditions, the operating handle or lever I is at one end(assumed to be the righthand end as seen in Fig. 2) of its stroke ortravel and the oating lever 9 is consequently in a correspondingposition so that the contact lever I4 is at the right-hand end of itsstroke in which the contact member II carried thereby is in engagementwith fixed contact I8a to which electric current is supplied frombattery 45 by way of contact I8 for effecting the energization of therelease magnet valve device 43 so as to establish communication betweenthe brake cylinder 44 and the atmosphere for effecting a release of thebrakes. In this position of the contact lever I4 an adjustable stop bolt3'I engages with a boss 38 on the casing 4 so as to define the positionof the contact lever.

When it is desired to effect an application of the brakes the handle orlever I is rocked towards the left, as viewed in Fig. 2 of the drawings.to an extent depending upon the degree of braking required. The initialpart of this movement rocks the oating lever 9 about its intermediatepivot I9 as a fulcrum so as to effect a corresponding rocking movementof the contact lever I4 about its xed fulcrum I5. Since the shorter armI3 of the contact lever I4 is coupled to the floating lever 9 and itslonger arm I6 carries the contact member Il, a relatively small initialmovement of the handle I will effect the rapid and full movement of thecontact lever I4 to its eXtreme left or application position. Duringthis movement the contact member II rst moves out of engagement withfinger |8a and then into engagement with nger |87) effectingdeenergization of the release magnet valve device 43 and energization ofthe application magnet valve device 42, thereby cutting offcommunication between the brake cylinder 44 and the atmosphere andeffecting the supply of uid under pressure from the main reservoir 45 tothe brake cylinder. An adjustable stop bolt 39 on the contact lever I4in this eXtreme position engages with a boss 40 on the casing 4 so thatfurther movement of the contact lever I4 is prevented after which thecontinued movement of the operating handle I causes the oating lever 9to rock about its pivotal connection I0 to the link II coupling this endof the floating lever 9 to the contact lever,|4 which is now stationary.

This 'rocking movement of the floating lever 9 causes the rod 2I to movetowards the left, as viewed in Fig. 2 of the drawings, within andrelative to the tubular piston rod 22, the head of the rod 2| carryingwith it the adjacent sliding collar 39 which accordingly compresses thespring 3E between the collar 30 and the other collar 29 which remainsstationary abutting against the shoulder 32 on the cap 33. The extent ofthis movement of the rod 2| will evidently depend upon the extent ofmovement of the operating handle I which in turn determines the brakecylinder pressure ultimately established in the following manner:

The energization of the application magnet valve device 42 causes fluidunder pressure to be supplied to the brake cylinder 44 as abovedescribed and the pressure thus obtained in said brake cylinder istransmitted through pipe 21 and passage 26 to the end 25 of the cylinder24 wherein said pressure acts upon the piston 23 and moves the lattertowards the left, as viewed in Fig. 2, against the opposing action ofthe control spring 28. This movement of the piston 23 is relative to therod 2| and will evidently continue as the brake cylinder pressureincreases until the shoulder 3| on the piston rod 22 engages with thestationary sliding collar 39 so that the rod 2| and the two collars 29,30 are again in their original positions relative to the piston rod 22.After this occurs the continued movement towards the left of the piston23 and piston rod 22 causes the rod 2| to move in the same direction androcks the oating lever 9 about its pivotal connection 8 to the link 'Ias a fulcrum so that the lower pivotal connection I0 of the floatinglever 9 is moved towards the left and turns the contact lever I4 in aclockwise direction away from its application position. This movement ofthe contact lever I4 disengages the contact segment I 'I from thecontact finger IBb and effects the deenergization of the applicationmagnet valve device 42 which then operates to cut olf the furthersupplyof fluid to the brake cylinder. The increase in brake cylinderpressure in the end 25 of the cylinder 24 acting upon the piston 23thereupon ceases and the movement of the contact lever I4 is arrested inan intermediate or holding position in which the application magnetvalve device 42 is deenergized while the release magnet valve device 43remains deenergized. It is desired to more particularly point out herethat the segment I 'I is so formed as to provide the holding or lapposition in which it engages neither of the fixed contacts I8a or |81).Regardless of the direction of movement of the contact member I'I italways disengages one of the xed contacts I8a or I8b before it engagesthe other.

If the operating handle or lever I is moved further towards the fullapplication position the floating lever 9 and the contact lever I4 areagain operated in a similar manner to that above described so as tocause the pressure of fluid in the brake cylinder 44 to becorrespondingly increased to a higher value and maintained at thisvalue.

If on the contrary the operating handle I is moved towards the releaseposition, i. e., turned toward the right hand, as viewed in Fig. 2 ofthe drawings, the initial portion of this movement causes the floatinglever 9 to be rocked about its intermediate pivotal connection I9 as afulcrum thereby causing the contact lever I4 to move to its releaseposition in which the segment I'I is moved out of engagement withcontact |8b and into engagement with contact |8a thereby deenergizingthe application magnet valve device 42 and energizing the release magnetvalve device 43 thus permitting the release of uid from the brakecylinder 44. The continued movement of the operating handle I effectsthe rocking of the floating lever 9 about its pivotal connection Il) tothe link II as a fulcrum and thus moves the rod 2| connected tothe`floating lever 9 towards `the right hand, as viewed in Fig. 2, withinthe tubular piston rod 22 carrying with it the left-hand 4collar 29 :andcompressing the spring 35. l

As the brake cylinder pressure decreases, the piston 2'3 and piston rod22 are 'permitted to Amove towards 'the right under the action of the`control spring 2.8 `until the collar '29 is restored "to its originalposition Within `the tubular 4piston rod 22 after which the continuedmovement of the piston '23 towards the right rocks the floating lever S9about its pivotal connection '8 to the link "I as a vfulcrum and movesthe contact lever T4 Vand -thereby contact I1 toits intermediate `orholding position, thereby cutting off the release 'of iluid from thebrake cylinder M and maintain- 'ing fthe brake cylinder Vpressure at theldesired reduced value.

From the above description it Will be evident that Whenever theoperating handle l is adjusted from one position to another from ortowards `its release or full application position, a small initialmovement of the handle effects through'the shorter and longer arms I3,I6 respectively of the contact lever I4 a rapid and relativelyconsiderable movement of the Contact member I1 as is required to eiectthe proper change `in lthe control circuit connections. -On the other`hand the range of subsequent movement of the handle l (compressing thelight spring `36 in the tubular piston rod 2'2) is of considerableextent thereby enabling the automatic adjustment of the brake cylinderpressure in accordance with the setting -of the handle i and lu'r'iderlthe action of the piston 23 to be accurately effected.

Theinvention is evidently not limited to the particular construction andlarrangement of the control device above described and illustrated byway of example which may be varied `in many respects without exceedingthe scope of the infor said lever, and yielding resistance meansoperative to hold said fulcru-m element stationary during movement ofsaid member to either of its positions by said manually operable meansand then yieldable to permit movement ci said fulcrum element by saidmanually operable means.

2. In a brake control apparatus, in combination, a brake control member,means operable upon movement of said member to one position to effect anapplication of the brakes and to another position to eiect the releaseof the brakes, manually operable means, a lever operatively connectingsaid manually operable means `with said member, a movable fulcrumelement for said lever, and yielding resistance means acting on saidfulcrum element to prevent movement thereof during movement of saidmember to either one or the other of its positions by said manuallyoperable means and then yieldable to permit further movement of saidmanually operable means relative to said member and means operative uponeffecting a predetermined application of the 'brakes for moving saidelement and :thereby .said lever and brake control member from the brakeapplication position.

3. In a brake control apparatus, in combination, a brake control member,Vmeans operable `upon movement of `said-member to one position to effectan application of the brakes and to another position to effect therelease of the "brakes, manually operable means, lever means operativelyconnecting said manually operative means Wthsaid member, and yieldingresistance means cooperative with said manually operative means toeffect movement of said member to one or the other of said positionsupon movement of said manually operative means and then yield- .able topermit movement of said manually opferable means relative to saidmember.

4. -In a brake control apparatus, in combination, a brake controlmember, Ameans operable upon movement of said member to one Aposition toeiTect an application of the vbrakes and to another position to `effectthe release of the brakes, manually operable means, lever meansoperatively connecting said manually operative means With said member,and yielding resistance means cooperative with said lever means uponopera-y tion of said manually voperative means to effect movement ofsaid member to one or the other of said positions and then yieldable topermit further `movement of said manually operable means, and meansoperative upon effecting a predetermined variation in the degree ofapplication of brakes to move said Ybrake control member to stillanother position.

'5. In a brake control apparatus, in combination, a brake controlmember, `means operable upon movement of said member to one position toeffect an application olE the brakes and to another position to eiectthe release lof the brakes, manually operable means vfor moving saidmember to either one or the other of said positions, yielding resistancemeans cooperative With said manually operable means to effect movementof said member to said positions and then yieldf able to manual pressureon said manually operable means whereby said manually operable means ismovable relative to said member, and means controlled by a predeterminedforce acting in opposition to a force proportioned to the degree ofapplication of brakes operative after a movement proportional to themovement of said manually operable means relative to said member to movesaid member to still another position.

6. In a brake control apparatus, in combination, a brake control member,means operable upon movement of said member yto one position to effectan application of the brakes and to another position to eiiect therelease of the brakes, stops for preventing movement of said member pastsaid positions, manually operable means for effecting the movement ofsaid brake control member, an element subject to 'a predetermined forceacting in opposition to a force 'which varies with the degree of brakeapplication for also effecting operation of said brake control member,and `yielding resistance means in the connection of said manuallyoperable means and said element to said member operable upon operationof said manually operable means to effect movement of said member to oneor the other of said positions and then yieldable to permit furthermovement of said manually operable means, and operative by said ele-`ment to effect movement of said member to a position intermediate saidpositions after movement of said element a distance proportional to saidfurther movement of said manually operable means.

7. In a brake control apparatus, in combination, brake control meansoperative to effect an application of the brakes and to supply to achamber fluid at a pressure proportional to the degree of brakeapplication, manually operable means connected to said brake controlmeans for eifecting the operation thereof, a lever in the connectionbetween said manually operable means and said brake control means, amovable fulcrum member for said lever, a spring, a movable abutmentsubject to the opposing pressure of said chamber and said spring, andyielding resistance means between said fulcrum member and abutment, saidabutment being operative after a predetermined increase in fluidpressure in said chamber to operate said fulcrum member and thereby saidlever and brake control means.

8. In a brake control apparatus, in combination, brake control meansoperative to effect a release of the brakes and to vary the pressure offluid in a chamber in accordance with the degree of brake application,manually operable means for controlling the operation of said brakecontrol means, a floating lever operatively connecting said manuallyoperable means with said brake control means, a movable fulcrum memberfor said lever, means for yieldingly opposing movement of said fulcrummember, a spring, and a movable abutment subject to the opposingpressures of said chamber and said spring and operative upon apredetermined reduction in fluid pressure in said chamber to operatesaid fulcrum member and thereby said brake control means.

9. In a brake control apparatus, in combination, brake control meansoperative to effect an application and a release of the brakes and tovary the pressure of fluid in a chamber in accordance with the degreethereof, a brake control member movable to one position for effectingthe operation of said control means to supply fluid under pressure tosaid chamber and movable to another position for effecting the operationof said control means to release uid under pressure from said chamber,manually operable means for moving said brake control member to eitherone or the other of said positions, a spring, a movable abutment subjectto the opposing pressures of said spring and chamber for moving saidbrake control member out of said positions, and yielding resistancemeans in the operating connection of said manually operable means andmovable abutment to said brake control member for opposing movement ofsaid brake control member to said positions by the operation of saidmanually operable means and for moving said brake control member out ofsaid positions by the operation of said movable abutment.

10, In a brake control apparatus, in combination, brake control meansoperative to effect an application and a release of the brakes and tovary the pressure of fluid in a chamber in accordance with the degreethereof, a brake control member movable to one position for effectingthe operation of said control means to supply fluid under pressure tosaid chamber and movable to vanother position for effecting theoperation of said control means to release fluid under pressure fromsaid chamber and movable to a third or intermediate position forpreventing either the release of fluid under pressure from or the supplyof fluid under pressure 'to said chamber, stop means for preventingmovement of said brake control member past its extreme positions,manually operable means connected to said brake control member formoving said brake control member toeither one or the other of itsextreme positions, yielding resistance means in the connection of saidmanually operable means with said brake control member cooperative withsaid manually operable means for moving said brake control member to itsextreme positions and then yieldable to permit further movement of saidmanually operable means relative to said brake control member, a spring,a movable abutment subject to the opposing pressures of said spring andchamber, and means including said yielding resistance means forming anoperating connection for said movable abutment to said brake controlmember whereby said movable abutment is operative to move said brakecontrol member to said intermediate position after movement of saidabutment proportional to said further movement of said manually operablemeans.

11. In a brake control apparatus, in combination, brake control meansoperative to effect an application and a release of the brakes and tovary the pressure of fluid in a chamber in accordance with the degreethereof, a brake control member movable to one position for effectingthe operation of said control means to supply fluid under pressure tosaid chamber and movable to another position for effecting the operationof said control means to release uid under pressure from said chamber,and movable to a third or intermediate position for preventing eitherthe release of fluid under pressure from or the supply of iiuid underpressure to said chamber, stop means for preventing movement of saidbrake control member past its extreme positions, a manually operablemember, a spring, a movable abutment subject to the opposing pressuresof said spring and chamber, and lever means including a yieldingresistance forming an operating connection of said manually operablemember and movable abutment with said brake control member whereby saidmanually operable member is operative to first move said brake controlelement to either one or the other of its extreme positions and is thenmovable relative to said brake control element, and said abutment isoperative to move said brake control means relative to said manuallyoperable member to said intermediate position.

12. In a brake control apparatus, in combination, brake control meansoperative to effect an application and a release of the brakes and tovary the pressure of uid in a chamber in accordance with the degreethereof, a brake control member movable to one position for effectingthe operation of said control means to supply fluid under pressure tosaid chamber and movable to another position for effecting the operationof said control means to release uid under pressure from saidchamber,and movable to a third or intermediate position for preventing eitherthe release of fluid under pressure from or the supply of uid underpressure to said chamber, stop means for preventing movement of saidbrake control member past its extreme positions, a lever for moving saidbrake control member to its different positions, a manually operablemember connected to said lever, a floating fulcrum member connected tosaid lever, a spring, a movable abutment subject to the opposingpressures of Said spring and chamber, yielding resistance meansinterposed between said abutment and floating fulcrum member foropposing movement of said fulcrum member upon operation of said manuallyoperable member and thereby said lever to move said brake control memberto its extreme positions and operative to oppose operation of saidmovable abutment upon a variation in fluid pressure in said'v chamber tomove said lever and thereby said brake control member to itsintermediate position.

13; In a brake control apparatus, in combination, brake control meansoperative to effect an application and4 a release of the brakes and tovary the pressure of fluid in a chamber in accordance with the degreethereof, a brake control member movable to one position for effectingthe operation of said control means to supply fluid under pressure tosaid chamber and movable to another position for effecting the operationof said control means to release fluidy under pressure from saidchamber, and movable to a third or intermediate position for preventingeither the release of iiuid under pressure from or the supply of fluidunder pressure to said chamber, stop means for preventing movement ofsaid brake control member past its extreme positions, a lever for movingsaid brake control member to its different positions, a manuallyoperable member connected to said lever, a floating fulcrum memberconnected to said lever, a spring, a movable abutment subject to theopposing pressures of said spring and chamber, an element connected tosaid floating fulcrum member and associated with said abutment andmovable relatively to said abutment longitudinally thereof in eitherdirection from a neutral position, spring means associated with saidabutment for opposing movement of the element from its neutral position,said spring means being operative to prevent movement of said fulcrummember relativel to said abutment until after said brake control memberis moved to one or the other of its extreme positions by the operationof said manually operable means and then yieldable to permit furthermovement of said manually operable member, said abutment being operativethrough said spring means to move said fulcrum member and thereby saidlever and brake control member to said intermediate position.

14. In an electro-pneumatic brake, in combination, a brake cylinder,electro-responsive means, a brake control switch means movable to anapplication position for eiecting the operation of saidelectro-responsive means to supply ilud under pressure to said brakecylinder, and movable to a release position to effect the release of uidunder pressure from said brake cylinder, and movable to a lap positionintermediate said application and release positions for holding fluidunder pressure in said brake cylinder, stop means engageable by saidswitch means in the application and release positions for preventingfurther movement of said switch means, a lever havingone end connectedto said brake control switch means for effecting operation thereof, amanually operable member connected to the opposite end of said lever, afloating fulcrum member connected to said lever intermediate said ends,a spring, a movable abutment subject to the opposing pressures of saidspring and a chamber in which the pressure of iiuid varies with that insaid brake cylinder, and yielding resistance means connecting saidfloating fulcrum member to said abutment and operative to preventmovement of said fulcrum member relativev to said abutment uponoperation of said manually operable member until after said switch meansengages said stop means in one or the other position of said switchmeans, and operative bysaid abutment after a predetermined degree ofmovement thereof to move said fulcrum member and thereby said lever andsaid switch means to said lap position.

15. In a brake control apparatus, in combination, a brake control membermovable a fixed distance in one direction to an application position foreffecting an application of the brakes and movable a; fixed distance inthe opposite direction to a lap position for holding the brakes applied,manual means having a predetermined zone of movement and operativeduring an initial relatively small movement in said zone to move saidmember to said application position, yielding means cooperative withsaid manual means to move saidI member to said application position andthen yieldable to permit further movement of said manual means in saidzone relative to said member, and means controlled by the degree ofbrake application and operative to move said member to lap position whenthe degree of brake application corresponds to the position of saidmanual means in said zone.

16. In a brake control apparatus, in combination, a brake control membermovable a fixed distance in one direction to a release position foreffecting a release of the brakes and movable a fixed distance in theoppositel direction to a lap position for holding the brakes applied,manual means having a predetermined zone of movement and operati-veduring an initial relatively small movement in said Zone to move saidmember to said release position, yieldingv means cooperative with saidmanual means to move said member to said release position and thenyieldable to permit further movement of said manual means in said zonerelative to said member, and means controlled by the degree of brakeapplication operative to move said member to lap position when thekbrake application isk released to a degree corresponding to the positionof said manual means in said zone.

17. In a brake control apparatus, in combination, a brake control memberhaving a neutral or lap position and movable thereiromin one direction afixed distan-ce to an application position for effecting an applicationof brakes and in the opposite direction a fixed distance to a releaseposition for effecting a release of brakes, manual means having apredetermined zone of movement for controlling said brake controlmember' and operative during an initial, relatively small movement inone direction in said zone to move said member to said applicationposition and in the opposite direction to move said member to saidrelease position, yielding means cooperative with said manual means toeffect movement of said member to either said application position or tosaid release position and then yieldable to permit movement of saidmanual means relative to said member, and means controlled by the degreeof brake application operative to move said member to lap position whenthe degree of brake application corresponds to the position of saidmanual means in said zone.

18. In a brake control apparatus, in combination, a brake control memberhaving a neutral or lap position and movable therefrom in one directiona fixed distance to an application position for eiecting an applicationof brakes and in the opposite direction a xed distance to a releaseposition for effecting a release of brakes. manual means having apredetermined zone of movement for controlling said brake control memberand operative duringan initial, relatively small movement in onedirection in said zone to move said member to said application positionand in the opposite direction to move said member to said releaseposition, yielding means cooperative with said manual means to effectmovement of said member to either said application position or to saidrelease position and then yieldable to permit movement of said manualmeans relative to said member, and mechanism set in motion uponinitiating an application of the brakes and upon initiating a release ofthe brakes to movesaid brake control member to said lap position after amovement of said mechanism proportional to the movement of said manualmeans relative to said member.

19. In a brake control apparatus, in combination, a brake control memberhaving a neutral or lap position and movable therefrom in one directiona fixed distance to an application position for eiecting an applicationof brakes and in the opposite direction a fixed distance to a releaseposition for effecting a release of brakes, manual means having apredetermined zone of movement for controlling said brake control memberand operative during an initial, relatively small movement in onedirection in said zone to move said member to said application positionand in the opposite direction to move said member to said releaseposition, yielding means cooperative with said manual means to effectmovement oi said member to either said application position or to saidrelease position and then yieldable to permit movement of said manualmeans relative to said member, mechanism controlled by the applicationand release of brakes and movable to a position corresponding to thedegree of brake application, and means including said yielding meansoperative by said mechanism to move said brake control member to saidlap position after a movement of said mechanism proportional to meanshaving a predetermined zone of movement' for controlling the operationof said brake control member to effect the application and release ofbrakes and operative during an initial, relatively small movement insaid zone in one direction to move said brake control member to saidapplication position and in the opposite direction to move said brakecontrol member to said release position, a spring, a movable abutmentsubject to the pressure of said spring and the opposing pressure ofiiuid in a chamber, in which the iiuid pressure varies with that in saidbrake cylinder, movable to a position corresponding to the pressure ofiluid in said brake lcylinder for moving said brake control member tosaid lap position, and resilient means in the connection of said manualmeans and movable abutment to said brake control member for moving saidbrake control member upon operation of either said manual means or saidmovable abutment and yieldable after said brake control member attainseither the application or the release position to permit movement ofsaid manual means relative to said brake control member, and operativeto delay operation of said brake control member by said abutment untilafter a movement thereof which is proportional to the movement of saidmanual means relative to brake control member.

ARTHUR G. KERSHAW, ARTHUR W. SIMMONS. KENNETH H. LEECH.

